1. Introduction
Introduction
There is no doubt, a remarkable progress in data storage
related technologies throughout the last 2 decades has opened new ways for excited
developments on every aspect of today?s computing systems. The constant need
for more and more free available storage space is accompanied by the need of
users to be able to transfer their data from system to system, in locations
where transfer by ?wire? over existing networks is uneconomical or even not
feasible at all. Moreover, all those multimedia files plumbing our hard disks
are desperately seeking their way to a safe backup place.
Two similar and in some respects complimentary technologies
come to support us (regular users) into solving these data transfer and backup
problems. They offer us optical recording devices with the accompanied media in
the form of a 12cm CD, CD-R, CD-RW, and DVD disks, and magneto-optical drives
making use of media sealed into 3.5?, floppy-factor, cases.
Fujitsu is a leading supplier of magneto-optical drives. Two
of these drives are the
MCE 3130 AP/SS (the first based on an ATAPI/IDE interface, the second on a SCSI), capable of reading and writing to 3.5?, 1.3
Gigabytes removable disks as well as to older smaller capacity disk types. The 1.3GB capacity disks (and the forthcoming 2.6 GB ones) might
be considered as direct antagonists to the latest Double Density CD format by
Sony and the Multilevel (ML) CD?s soon to be offered by Plextor and other
manufacturers. Offering similar storage characteristics as these other new
formats, the magneto-optical drives by Fujitsu promise to deliver three
distinct advantages, each of which is known to break existing technology
shortcomings by which suffer pure optical recording drives:
- Short media access times, approaching those of fixed
disks.
- Very large numbers of repeated media erasure and
re-recordability. In fact, the reusability of the magneto-optical disks far exceeds that of even the DVD-RAM and DVD+RW formats.
- Smaller media cases. Actually the disk area of these disks is about on fourth of
of the competing optical disks.
We provide some complimentary material, along with a critical approach to the relevant technologies at an Appendices of this review. For now we will strive to justify
all of the above claims (at least those feasible for a publication aiming to
end-user attention).
We start by presenting in the following section a brief
review of magneto-optical technology. We will then focus on particular
characteristics of the MCE-3130-AT/SS drives and we will carry out a series of
tests for assessing their performance. We hope the reader will find rewarding our effort.
2. An outline of Magneto-optical technology
An outline of Magneto-optical technology
Let us first understand how writing and reading takes place on a magneto-optical medium.
(The various graphs we will use below for illustration purposes are due to
Fujitsu, Konica and other manufacturers of the magneto-optical alliance).
Write/erase cycle
Inside a 3.5? case, the MO disk consists of a series of
layers, each one of them offering support to distinct aspects of the
implementation of the respective technology.
First, a ?high? power laser-beam raises the temperature of a
particular point at the active layer on a MO medium. When at the same time BIAS magnetic field
is applied perpendicularly to the medium, the local temperature of the particles at the region of this point goes up to the "Curie point (180-200 °C). Then, the
direction of magnetization on this particular point becomes reverse (angle
change). After the laser beam is switched off, the magneto-optical layer cools
down very rapidly. The information is then fixed on
the medium and it can be altered only by using a laser beam and a BIAS magnet
again. The data is more securely stored compared to conventional magnetic
disks, on which even a small magnet can cause loss of data.
The operation of erasure follows the same principles as above.
Direct overwrite technology (DOW)
With conventional MO recording technology, 3 rotations
(erasing, writing and verification) are necessary to write data onto a disk. A new
MO recording technique, called Laser Intensify Modulation - Direct Overwrite (LIM-DOW),
enables the erasing and writing functions to occur simultaneously; i.e.,
the writing operation can be performed by only one rotation (direct overwrite).
Taking into account that due to current limitations of the new technique the rotation speed of the disk is forced to be lower during writing, the LIM-DOW technology delivers just 1.5 times faster
writing performance than traditional writing methods (instead of a 3-fold speed increase as expected). This technology requires that the laser
and the other drive electronics that control the functioning of the beam to be able to modulate at 3 distinct levels. Additionally, new media should be formulated containing 6 different layers. These
layers consist of different material mixtures as follows: Read out layer (GdFeCo),
Memory layer (TbFeCo), Intermediate layer (GdFeCo), Writing layer (DyFeCo),
Switching layer (TbFeCo), and Initializing layer (TbFeCo).
The reading operation
When reading data on the MO disk, the application of an
external magnetic field is not required. The entire reading operation is
processed optically. A laser beam with less energy than that used for the
writing process is projected to the MO disk to detect the points that where polarized
during writing. Then, the polarized angles are converted to electric signals.
Demodulation and error correction is then applied to deliver the 1?s and 0?s of the
originally written information on the disk.
The MSR Technology
To achieve more than 1GB of written data onto a single disk,
a new optical detecting scheme has been developed by Sony and Fujitsu called
MSR (Magnetically induced Super Resolution) technology. The MSR technology enables
doubling of track-density and recording-density while being able to keep full compatibility with
respect to the original ISO Standards for Magneto-Optical recording.
GIGAMO™ is the name of the new standard for the case of 3.5-inch
magneto-optical disks. It can achieve capacities of 1.3GB per disk, or more (2.6 are on the horizon and 5.2 and 9.1GB are promised to follow). Please note that GIGAMO
is not the name of any particular MO product.
The GIGAMO standard specification is based on media of
identical physical dimensions with earlier MO disk formats. Both disk drives
and cartridge cases based on the current ISO/IEC standards are fully utilizable
on drives based on the new technology. As a matter of the MO alliance
manufacturers? decision it thus retains full compatibility with all existing
media. In many cases existing disk writing/reading speed performance increases.
This will be exhibited in the following test sections.
GIGAMO was jointly developed by Sony and Fujitsu, with Sony
taking responsibility for the media and Fujitsu for the disk drive development.
Major drive manufacturers such as Olympus and Konica, and
media makers like Kyocera, Teijin, Toso, Hitachi- Maxell, Mitsubishi Chemical,
Phillips/PDO, and recently Ritek (the largest Chinese
optical/magneto-optical media manufacturer in Taiwan mainland) have all agreed
to support the new GIGAMO standard.
The reader can find more details on MSR technology in
Appendix II of this review.
3. Specifications and installation of the tested drives
Specifications and installation of the tested drives
The specifications of the two drives of our review, as
provided by the manufacturer itself, are as follows:
| MCE 3130 AP |
MCE 3130 SS |
| 1.3GB internal drive
with ATAPI interface |
1.3GB Ultra-SCSI
internal MO drive |
| Fast internal data
transfer rate: up to 5.9MB/s. |
Fastest internal
data transfer rate: up to 6.7MB/s |
| High rotational
speed: 3,214 rpm / 4,558 rpm* |
Highest rotational
speed:
Normal mode: 3,637 rpm (1.3GB disk) / 5,455 rpm (other disks)
ZLCV mode*: 3,637 - 4,801 rpm (1.3GB disk) |
| Excellent random
accessibility: 23 ms seek time |
Fastest seek time:
19 ms |
| Full read/write
compatibility with 1.3GB GIGAMO disks and all ISO 3.5" MO disks (640MB,
540MB, 230MB and 128MB) |
Full read/write
compatibility with 1.3GB GIGAMO disk and all ISO 3.5" MO disks (640MB,
540MB, 230MB and 128MB) |
| *MCE3130AP has two rotational speed modes with 3,214 rpm for
a 1.3GB disk and 4,558 rpm for other lower capacity disks. |
*MCK3130SS automatically activates ZCLV mode for sequential
multimedia files and controls the rotational speed ranging from 3,637 rpm up to
4,801 rpm using 1.3GB disks. |
In the following section we will perform a series of exhaustive tests to find out whether these claims stand on their own or not.
Other 1.3GB drives by
Fujitsu
The following drives use the same basic mechanism, but utilize a
different interface:
All three drives appear on the market today at a higher price than the standard ATAPI drive we tested. (It seems the Fujitsu marketing department does not consider they fulfill basic end-users' needs...)
Installation
In the front cover of both drives there is the GIGAMO logo.
The ATAPI model has the MO 1.3GB logo on the right of the tray as well.
On the front panel there is an eject button and an emergency eject hole (as expected).
Since both drives aim to be compatible with a wide platform
hardware, there are ample jumpers at the rear end of both. The following guide
instructs the user on the switch and jumper settings in the MCEMCE3130SS model
during installation. The factory default settings are marked with an asterisk.
The following SW1 (Switch 1) sets the SCSI ID and some other drive
functions.
CHN1 (external switch setting) sets the power and SCSI termination. It uses shorting bars to set the power source and
to enable or disable SCSI termination.
The CNH2 (external switch setting) sets additional drive functions.
Most current OS?s have build-in support for MO devices.
There might be some problems with Win95 or WinNT (earlier than version 4.0), so
Fujitsu suggests using their installation drivers package. The drivers also
install a .VXD driver in order to increase the reading/writing performance of
both IDE/SCSI models on these operating systems. So any user still using these OS's is advised to install them.
To install the drives we used the version 5.01E software package
provided at the Fujitsu?s Japanese site. After installation, Windows Me
correctly recognized the drives as Fujitsu MCE3130AP and MCE3130SS
respectively.
Fujitsu suggests not to enter any disk in the drive, before
you turn if on. Upon its first power on, the drive will make a ?click? sound
and afterwards you can use it without any problems.
Of course, MO optical drives work only with formatted media. Fujitsu
provides the ?MO Disk Formatter? utility, a media formatting software. This software is
not needed under Windows 2000 or later. Right-clicking on the MO drive?s icon under
Windows Explorer the option of formatting the disk is offered. (Please take note that
if you decide to perform a low-level format, such as in the case where the disk
has been damaged or severely overused, you will need to use the supplied
software even under Windows 2000!)
Let?s have a look at this software.
First, select the MO drive. (If there is no MO disk in the
drive, the message ?No disk in the drive? is displayed.) The MO disk formatter
supports both floppy and hard disk type formats (FAT 16/FAT 32) so that it can be used as a large capacity floppy disk. This format can be used on almost all machine types and operating systems. (The FAT 32 format type
can make use of a greater number of clusters than FAT 16, using a smaller
cluster size. It is supported on Windows 95 OSR 2 or later operating systems by
Microsoft.)
This program cannot set multiple partitions on a single
disk. It seems this is a restriction of the drivers and is probably due to a
lack of interest in part of the manufacturers to define such a layered logical
format for the MO disks.
The user is also offered the option of performing a low level disk
format. This type of format scans the entire MO disk in order to optimize its
performance and takes 15 to 20 minutes (for the 1.3GB disk). Low level formatting is recommended for
older, heavily used MO disks. (Note that low level formatting cannot be
canceled once it is started.)
The program also indicates the sector size and the capacity
of the MO disk inserted. The sector
size in this screen is the number of bytes per sector. While the
?raw? sector size is always 1 kilobyte long, the logical sector size can be defined on this screen of the
program.
It can be
set to 4 or 2Kbytes in the options tab. This function is allowed when Floppy
Type (FAT 32) or Hard Disk Type (FAT 32) is selected and only when the disk
size is 540MB or greater. As said above, FAT 32 Formatted MO disk can save the data more
efficiently. (However, an operating system that supports FAT 32 is required to
use FAT 32 formatted disks.) You can also set a name to the disk in the "Volume Label"
textbox, which can contain up to 11 characters with alphanumeric characters and the
_ symbol (underscore).
4. Performance tests
Performance tests
We assessed the writing and reading performance of the
MCE3130SS Ultra-SCSI and MCE3130AP ATAPI MO drives using SCSI Mechanic v.3.0 as the testing software. We
tested both drives with MO disks of varying capacities supplied to us by Fujitsu. The disk capacities
were 1.3GB, 640MB, and 540 MB. We also tested the drives using
230MB disks manufactured by Verbatim. For all our tests we formatted the disks under HD-FAT32. The DMA option was enabled for the IDE model during our tests and also Sync Data
Transfer option was set on for the SCSI model tests.
Test machine
- OS: Windows Me
- Processor: AMD 650 MHz
- M/B: QDI K7V8363 KINETIZ 7T, 128MB SDRAM
- H/D: WD 10.2 GB UDMA 66
The results are
shown in the chart below.
SCSI MECHANIC RESULTS
| |
Media Read |
Media Write |
| MO Drive |
Disk
Capacity |
Random |
Sequential |
Butterfly |
Random |
Sequential |
Butterfly |
MCE
3130 AP |
1.3GB |
1722 |
3504
|
1085
|
837
|
933
|
580
|
| 640MB |
1285 |
3108
|
974
|
750
|
1320
|
666
|
| 540MB |
1256 |
2593
|
925
|
565
|
800
|
468
|
| 230MB |
853 |
1615
|
735
|
501
|
640
|
326
|
MCE
3130 SS |
1.3GB |
1732 |
3496
|
2193
|
611
|
1330
|
1331
|
| 640MB |
1308 |
3103
|
2158
|
775
|
1660
|
3103
|
| 540MB |
1252
|
2600
|
1963
|
560
|
1820
|
1300
|
| 230MB |
852
|
1521
|
1530
|
375
|
2630
|
920
|
The following charts provide a visual presentation of the above data
and present a reading and writing performance comparison among the various MO media. All disks were tested in
random, sequential and butterfly mode access modes.
In the random access test, MC 3130AP manages to reach a 1722
Kb/sec transfer rate while reading from the Fujitsu 1.3GB MO disk. Rates seem
to be lower when the drive reads from 640MB or lower capacity disks. It seems that LIM-DOW technology has not matured yet. The simultaneous use of both land and groove bits forces the drive to spin at a lower speed!
The sequential reading performance climbs to 3504kb/s for
the 1.3GB disk and becomes lower as the tested media are of lower capacities.
The same reading behavior appears also in the butterfly reading tests, where the
transfer rates start from a 1085kb/sec (1.3GB) transfer rate to gradually come
down at a 735kb/s rate for the 230MB disk. It seems as the rate difference in
this case diminishes. Older (and thus lower capacity) disk formats compete more
efficiently with newer (and presumably) more efficient disks. This is normal, however, as this type of test
exercises heavily the pickup head in seek time loads. As this time decreases
only marginally at the newer formats, this behavior is normal.
In the random writing performance tests, MC 3130AP gave an
837 kb/sec transfer rate when used with 1.3GB MO disks. Sequential writing test
gave an unexpected result for the 640MB disk. The 1320 kb/sec transfer rate is
the best among the other media performances, including the 1.3GB disk.
The same applies to the butterfly tests as well. This obviously reveals a
better compatibility of MC 3130AP with 640MB media in writing sessions, and is
due to limitations of the current drive series in dealing with media recorded
both in land and grooves. We expect this to change when newer drives compatible
with the 1.3GB medium will be introduced.
As you can see in the chart on the left, the MC 3130SS model
has the same transfer rate performance as the ATAPI model in the random and
sequential tests. The results are better in the butterfly tests, where the
transfer rates are much higher than those offered by the ATAPI model.
In the random writing tests, the 640 MB disk offered the best
performance (775kb/sec) among the other media tested. The sequential writing
results place the 230MB disk in the first position with a 2630 kb/sec transfer
rate. The 540 MB disk is in the second place, giving a 1820kb/sec rate. The 640
MB disk performed better in the butterfly test, where it gave the highest
result (2103kb/sec). The 1.3GB and 540BM media gave the same transfer rates,
approximately 1300kb/sec and finally, the Verbatim 230MB disk performance, reached
only 920kb/sec.
Considering the test results above, we could say that the
Fujitsu MC 3130AP (ATAPI) and MC 3130SS (SCSI) models behave almost the same
when reading the various MO media. The main performing
differences come in the writing sessions, where the SCSI model seems to give
higher transfer rates. This is certainly not due to any BUS superiority, as this would apply in the reading case as well. We may thus safely assume that it is due to a firmware restriction. Probably the SCSI models are based on a higher quality lasers! (Might it be the case that during production the best apparatus is probably used on the SCSI models, and those passing the quality tests next are used for the ATAPI models?)
We also tested the access times of the drives
using same media capacities as previously. The software that was used in this case was the Ziff Davis
?Media?s WinBench 99 v.1.2?. The ATAPI model gave the same access time results
as the SCSI drive. The best performance (36.1 msec) comes from the lower capacity
disk (230MB). The drive accessed the 540MB and 640MB disks at an average of 37
milliseconds throughout the media?s surface. The highest access time was given
when the tested media had a capacity of 1.3GB.
5. Conclusion
Conclusion
Fujitsu Magneto-optical (MO) drives seem to be an attractive
proposal for the user who needs an alternative, to the
plain old compact disk, removable storage medium format.
Serving multiple functionalities, the Fujitsu MO drives can
be used as a secondary Hard Disk (1.3GB) of a lower however capacity, a descent backup solution for
moderately sized user data, or a high capacity floppy disc for everyday
office-to-home file transfers. With installation and usage simplicity, even
novice users who are asking for an economical and reliable solution can easily
adopt MO drives. Buffer underruns and drive-to-media incompatibilities from
which frequently suffer other formats, such as the compact disks, are unknown
to MO drives and media.
On the other hand, with cartridges that are impervious to
dust, moisture, and shock, Fujitsu MO disks are extremely rugged and highly
tolerant of the problems that plague regular magnetic media.
It is important to take into account when making your own assessment that each MO disk comes with a lifetime warranty.
The power point of Fujitsu MO drives is the low random
access times. Officially Fujitsu claims that MO drives can randomly access a MO
disk at an average of 23msec. Our tests showed a access times in the area of 35msec. As for the transfer rates achieved, they are lower
than those an optical CD-R drive can give today.
However, the MO technology will not disappoint the candidate
MC 3130AP or MC 3130SS buyer. Fujitsu is already developing the 2.3GB MO line
of drives, while it has promised the even larger capacities of 5.2 and
9.1GB per disk.
The reader might also read the appendices to this review by clicking the relevant links below and to the right.
6. Appendix I. Fixed Storage versus Removable storage
The evolution of optical data storage
technologies
Today?s hard disk devices support gigantic capacities,
allowing the storage of large amounts of data with high availability and
safety. When we talk about storage, we usually have in mind the hard disk
drives. Fixed hard disk drives offer almost everything a home
or office user needs. All except an easy method of transferring data between
different computer systems. Furthermore, they are not immune to magnetic field radiation and by no
means can they be considered a permanent storage solution. The read signal
deteriorates in a few year?s period.
But what about our everyday desktop needs for removable,
reliable and economical storage? The (not too much) unexpected explosion in CD recordable/rewritable
drives sales over the period of the last few years, have prompted optical media
into a leading position in the removable data storage category. Optical and magneto-optical drives now offer the same
alternative solutions once offered by the floppy discs, now an area occupied by
Compact Disk.
Removable media technology is currently lagging
fixed-storage achievements in both raw performance and price cost per available
disk space offered. For example, compare the 40MB hard disks embodying the
early 1990?s PCs with the 15GB per disk standard capacity of a typical system
today. A 30-fold increase in available storage, with a marginal decrease in
cost!
In contrast, a DVD-ROM drive typically equipping a modern
PC, offers just an 8-fold available disk space increase, at about the same
amount of money.
In the case of MO media technology, and during the same as
before time-frame, we went from a 3.5", 128MB disk available to consumers during the
first MO device shipments of Fujitsu in early 90?s, to 1.3GB disks capable drives today.
Roughly the same overall capacity increase as in the case of the more commonly
available optical disks.
The Fujitsu proposition
Fujitsu, Japan, is the leading manufacturer of a series of
magneto-optical. Starting from the original 128MB magneto-optical (MO) media in
early 90?s, it now offers modern drives capable of reading/writing media of an
1.3GB capacity, with a soon to be released 2.6GB capable drive, all the way up
to a promised drive that will be able to use 9.1GB media!
However, the bigger the capacity
of a removable disk and the greater its price cost is, the more it grows the
user?s concern on its reliability. Fujitsu has an alternative solution
for removable storage: The MCE3130 Magneto-Optical (MO) internal drive series.
According to Fujitsu, a magneto-optical disk drive, is a computer data
storage device covering the most of the features and properties wanted and needed
by desktop computer users. It can store large amounts of digital data - digital
still photos, video clips, Internet downloads, and of course any size text
files - easily, quickly and securely.
As can be seen in the side picture, the MO disk, the
heart of the system, is almost the same size as a standard floppy disk. The
available media capacities are 128MB, 230MB, 540B, 650MB and 1,3GB made by
Fujitsu, Maxell, PDO Media, Sony, Teijin and Verbatim. A MO
disk can easily store 850 times more data than a conventional 1.44MB floppy,
that's 1.3GB of information in one MO disk. The 1.3GB media are based on
GIGAMO, which, as explained in an earlier section, is a new 3.5-inch magneto-optical technology standard,
featuring the Magnetically induced Super Resolution (MSR) technology.
7. Appendix II. MSR technology details
Appendix II. MSR technology details
The following picture shows the exactly how the magnetic
mask mechanism is implemented on the various media layers.
The Reading and Middle layer have different temperature
distributions (from low to high) relative to the elapsed time, as the laser beam, due to the disk rotation, comes over a particular bit of the disk and is irradiated.
In the part of the disk where the temperature is low, the magnetization of the particles in the middle layer is directed in parallel to the externally applied field. Subsequently, the particles in the reading layer are set
to the same orientation regardless of the orientation of the recording layer. Thus a front mask is created as shown at black spot on the side picture.
In the part of the disk where temperature is high, because of the fact that the particles in the middle layer
have been heated at a temperature higher that that of Curie point, the magnetization is lost. Consequently, at of the reading layer each particle is magnetized in the direction of the applied magnetic
field. This creates a rear mask, the white spot in the picture.
Only a part of the disk in the middle layer characterizes the direction at which the recording layers are magnetized. This allows an easy distinction of the polarization of the data bits and easily enables the drives electronics to recover the recorded data.
The gain of recording density is clearly shown in the
picture below, where you can see the read out (analog) signal differences between MSR
and normal MO reading.
In short, MSR Technology aims to reduce the interference among
neighboring recorded bits (intersymbol interference). Magnetic interference is
a phenomenon by which suffer not only MO but pure magnetic media as well. In our case
it emerges when reading from two or
more consecutive polarized spots (bits). Intersymbol interference limits the attainable recording density. As it
can be seen in the relative graph, MSR encloses each spot in a magnetic mask
creating an appropriate magnetic isolation which enables an easier detection of the relative peaks in the analog waveform readout. According to Fujitsu, the
application of the MSR technology can increase the recording density by 2 to 4
times.
The table below lists major characteristic values of the relevant specifications for each MO
media
type.
| |
Disk Capacities |
|
|
128MB
|
230MB
|
540MB
|
640MB
|
|
Track pitch
[micro-m]
|
1.60
|
1.39
|
1.10
|
1.10
|
|
Modulation
|
RLL2-7
|
RLL2-7
|
RLL1-7
|
RLL1-7
|
|
Sector length [bytes/sector]
|
512
|
512
|
512
|
2048
|
|
Linear density [micro-m/byte]
|
8.7 to 13.7
|
7.1
|
4.0
|
4.0
|
|
Bit transfer rate [M Bit/Sec]
|
21.8
|
26.1 to 41.8
|
35.0 to 58.8
|
34.9 to 58.1
|
|
Maximum frequency of data
|
7.25MHz
|
13.92MHz
|
14.71MHz
|
14.54MHz
|
From the above table we can see that while since mid 90's all hard disks employ PRML (partial response, maximum likelihood) encoding schemes, all MO drives (up to those tested here) employ pure peak detection (RLL).
The newer 2.6GB, 5.2GB and 9.1GB disk formats will be encoded under a PRML scheme. Perhaps part of the reason that these larger capacity disks will be attainable might be the employment of this newer encoding technology.
Unfortunately, unlike the CD and DVD format cases, where there is abundance of available technical information to the public, in the case of MO recording we were unable to obtain the necessary technical information. It seems that the MO disk alliance wants it to be this way:)
8. Appendix III. Mini FAQ for MO drives
Appendix III. Mini FAQ for MO drives
The following is based to a large extend on information provided by the relevant drive and disk manufacturers. It is included here purely for user convenience.
1. Why do MOs have a
high resistance to dirt and scratches?
Data is written to
and read from the recording layer of an MO disk through a thick polycarbonate
substrate. The diameter of the laser beam is wide at the point where it strikes
the disk surface, but becomes narrower towards the recording layer. Therefore, dust and
scratches on the disk surface hardly affect the generated signals.
Even if the disk surface has a large piece of
dust or a deep scratch that is likely to affect the signals, the employed"powerful" error
correction scheme can reproduce the original signals correctly. Since the
optical pickup DOS not come in contact with the disk and is separated from its
surface by approximately 1mm, there is almost no chance that the disk surface
will get scratched due to dust.
Moreover, remember that as in the case of DVD-RAM disks the disk is sealed into a case. Our experience suggests that 95% of all disk reading problems from disks that originally had no defects, comes from incorrect handling in part of the user!
2. Why are MOs
unaffected by magnetic fields?
The recording layer
of an MO disk is made by TbFeCo, a material that has extremely high coercivity.
The MO drive projects a laser beam to heat up the magnetic substance to a
temperature at which it loses its magnetism, and then starts writing data. MO
disks can still record in the presence of weak magnetic fields, but not at normal
room temperatures. Therefore, bringing a conventional magnet close to an MO disk
at room temperature will not corrupt the data on the disk.
Possible MO operation problems
3. Scan Disk takes an extremely long time, and I had to cancel
the operation. What do I do?
There is a possibility that physical or logical format
information was corrupted when the formatting operation was interrupted. If the
disk is in a state in which it can be formatted physically, use the formatter
that came with your device driver to format the disk physically, then reformat
it in MS-DOS format, and you should be able to use the disk again. Remember
that if you format a disk, any data on it will be destroyed.
On Windows 95, an unformatted disk cannot be "quick
formatted." Use "normal formatting."
4. I inserted a disk into the drive, but it is not
recognized
Data on the disk is unreadable. Check that your disk is formatted. Alternatively, logical format information may be corrupted. Use commercial
repair software to find out how severe the damage is, and repair it,
accordingly.
Dirt on the disk or
lens sometimes prevents the disk from being recognized.
5. Data cannot be written. Running ScanDisk or Norton utilities results
in a "Defective clusters generated" message. What do I do?
First, make sure that the disk is not write-protected. The drive may not have enough recording power (due to dirt
on the lens, laser deterioration, etc.) or the disk may be dirty.
6. Why can't 540 MB and 640 MB disks be used?
Check the manual of your drive and see if it is compatible with
540 MB or 640 MB disks. (If your disk is for 128 MB/230 MB size disks, 540 MB
or 640 MB disks cannot be used.)
On a 640 MB disk, one sector holds 2,048 bytes. On 540 MB,
230 MB and 128 MB disks, one sector contains 512 bytes. To use a 640 MB disk on
Windows 3.1 or MS-DOS, you need the proper device driver for 640 MB disks.
Check with your dealer.
7. Why does my disk drive misidentify the inserted disk
and hang up when I exchange a 128 MB/230 MB/540 MB disk with a 640 MB disk?
Exchanging a 128 MB/230 MB/540 MB disk (512 bytes per
sector) with a 640 MB disk (2,048 bytes per sector) may sometimes cause this
problem. Restart your computer before inserting a disk with a different sector
size.
8. After I attempted to copy a file, I received a message
saying "Too many files exist," and could not copy the file although
there was enough free space. Why?
If an MO disk is formatted in Super-Floppy format, only 512
folders or files can be stored under the root directory. If you attempt to
create any more folders or files, you receive this error message. Delete any
unneeded files and create a new folder, then copy the new file to the folder.
Drive supplier provides a device driver to avoid this problem. Install the
device driver before you use a MO drive.
9. A DOS/V formatted disk cannot be accessed on Windows
NT 4.0. Why?
Because Windows NT 4.0 has its own format, certain types of
disks cannot be accessed. Use the disk administrator to allocate the areas and
reformat the disk.
10. Disks used on Windows 95, Windows NT 3.1 or Windows
3.1 cannot be read on Windows NT 4.0. Why?
As described above, certain types of disks may be unreadable
due to differences in format, even if the device drivers you are using can
support these disks.
11. What are the advantages over competing
formats? (ZIP)
- High capacity. MO (1.3GB) can store 5 pieces of Zip Media (250MB) data in a
one media.
- Low media cost. Media cost of the Zip media is $0.06/MB, on the other hand
MO is only $0.019/MB.
- Large range of capacities can accommodate a wide variety of
applications.
- High compatibility.
12. Advantages over CD-R/RW
- Small disk size.
- High reliability.
- High transfer rate (not according to our tests anymore).
- No need for writing software.
- Windows 95/98 includes MO standard driver software.
10. Disadvantages over
competing formats
To be completed based on actual user feedback we will receive:)